Range hood

ABSTRACT

A range hood includes a housing, a cover, an exhaust pipe and at least two vacuum fans. The housing has a top and bottom openings opposite to each other. The cover is disposed in the housing and adjacent to the bottom opening. The cover has an air inlet facing the bottom opening. The exhaust pipe is disposed in the housing and located between the top opening and the cover. The exhaust pipe has an air outlet adjacent to the top opening and communicates with the cover. The vacuum fans are disposed in the cover and located between the air inlet and the exhaust pipe. Each vacuum fan has an air flow inlet adjacent to the air inlet and an air flow outlet adjacent to the air outlet. An area of the air inlet is greater than or equal to an area of the air flow inlets.

CROSS-REFERENCE TO RELATED APPLICATION

THIS APPLICATION CLAIMS THE PRIORITY BENEFIT OF CHINA APPLICATION(CN201721416490.9 FILED ON 2017 Oct. 30). THE ENTIRETY OF THEABOVE-MENTIONED PATENT APPLICATION IS HEREBY INCORPORATED BY REFERENCEHEREIN AND MADE A PART OF THIS SPECIFICATION.

FIELD OF THE INVENTION

The invention relates to a range hood, and more particularly to alow-noise range hood.

BACKGROUND OF THE INVENTION

As society develops and changes, the composition of the family haschanged from a large-size family in the past to small-size familynowadays. Particularly in Asian countries with high population density,the spatial boundary between a living room and a kitchen/dining room ina house trends to become increasingly blurred. With the popularizationof mobile devices such as smart phones, functions of a living room aregradually being replaced. Most family members used to spend timechatting in a living room, however, they now get used to doing so in akitchen/dining room. In light of general cooking habits, frying food byway of raging fire and hot oil makes loud noise; meanwhile, it alsoproduces an unpleasant smell of fumes. Therefore, a range hood equippedwith a fume exhaust system is a fundamental domestic appliance in akitchen/dining room. Noise control for range hoods sold on the marketnowadays is set as 65 dB (deci-Bell), and most range hoods, whileoperating, make noise of approximately 65 dB. Nonetheless, whenexceeding 55 dB, the noise interferes with regular conversations, and isprone to discomfort people. Even though most range hoods are equippedwith a multi-section adjustable system so that users can turn down airflow according to usage requirements in an attempt to keep noise made bya range hood less than 55 dB, fan's air flow and static pressure willsimultaneously lower dramatically resulting in incapability ofexhausting fumes thoroughly.

The information disclosed in this “BACKGROUND OF THE INVENTION” sectionis only for enhancement understanding of the background of the inventionand therefore it may contain information that does not form the priorart that is already known to a person of ordinary skill in the art.Furthermore, the information disclosed in this “BACKGROUND OF THEINVENTION” section does not mean that one or more problems to be solvedby one or more embodiments of the invention were acknowledged by aperson of ordinary skill in the art.

SUMMARY OF THE INVENTION

One objective of the invention is to provide a range hood with both oflow noise and high fume-exhausting performance.

Other objectives and advantages of the invention can be furtherunderstood from the technical features disclosed in the invention.

In order to achieve one or a portion of or all of the above objectivesor other objectives, the invention provides a range hood, which includesa housing, a cover, an exhaust pipe and at least two vacuum fans. Thehousing has a top opening and a bottom opening opposite to each other.The cover is disposed in the housing and adjacent to the bottom openingof the housing. The cover has an air inlet facing the bottom opening.The exhaust pipe is disposed in the housing and located between the topopening of the housing and the cover. The exhaust pipe has an air outletadjacent to the top opening and communicates with the cover. The atleast two vacuum fans are disposed in the cover and located between theair inlet and the exhaust pipe. Each of the at least two vacuum fans hasan air flow inlet adjacent to the air inlet and an air flow outletadjacent to the air outlet. An area of the air inlet of the cover isgreater than or equal to an area of the air flow inlets of the at leasttwo vacuum fans.

In summary, according to the embodiments of the invention, the structureof the range hood optimizes the airflow field of the inflow and outflowof air. The airflow field during the whole fume-exhausting process istapered in a multi-section manner so as to achieve smooth exhaustion offumes, improve the flow resistance of the range hood, and further reducenoise. In addition, by the components such as the blower fan and thebaffle, the range hood of the embodiments of the invention prevents thefumes from diffusing to the outside of the range hood so as to improvethe efficiency of fume exhausting.

In order to make the aforementioned and other features and advantages ofthe invention comprehensible, several exemplary embodiments accompaniedwith figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic view of the structure of a range hood inaccordance with an embodiment of the invention;

FIG. 2 is a schematic bottom view of the range hood shown in FIG. 1;

FIG. 3 is a schematic diagram of the resistance difference between therange hood of the invention and the conventional range hood;

FIG. 4 is a schematic diagram of the noise flow curve difference betweenthe range hood of the invention and the conventional range hood;

FIG. 5 is a schematic bottom view of a range hood in accordance withanother embodiment of the invention;

FIG. 6 is a schematic bottom view of a range hood in accordance withanother embodiment of the invention; and

FIG. 7 is a schematic view of the structure of a range hood inaccordance with another embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings which form a part hereof,and in which is shown by way of illustration specific embodiments inwhich the invention may be practiced. In this regard, directionalterminology, such as “top”, “bottom”, “front”, “back”, etc., is usedwith reference to the orientation of the Figure(s) being described. Thecomponents of the invention can be positioned in a number of differentorientations. As such, the directional terminology is used for purposesof illustration and is in no way limiting. On the other hand, thedrawings are only schematic and the sizes of components may beexaggerated for clarity. It is to be understood that other embodimentsmay be utilized and structural changes may be made without departingfrom the scope of the invention. Also, it is to be understood that thephraseology and terminology used herein are for the purpose ofdescription and should not be regarded as limiting. The use of“including”, “comprising”, or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless limited otherwise, the terms“connected”, “coupled”, and “mounted” and variations thereof herein areused broadly and encompass direct and indirect connections, couplings,and mountings. Similarly, the terms “facing”, “faces”, and variationsthereof herein are used broadly and encompass direct and indirectfacing, and “adjacent to” and variations thereof herein are used broadlyand encompass directly and indirectly “adjacent to”. Therefore, thedescription of “A” component facing “B” component herein may contain thesituations that “A” component facing “B” component directly or one ormore additional components is between “A” component and “B” component.Also, the description of “A” component “adjacent to” “B” componentherein may contain the situations that “A” component is directly“adjacent to” “B” component or one or more additional components isbetween “A” component and “B” component. Accordingly, the drawings anddescriptions will be regarded as illustrative in nature and not asrestrictive.

Please refer to FIG. 1 and FIG. 2. FIG. 1 is a schematic view of thestructure of a range hood 1 in accordance with an embodiment of theinvention. FIG. 2 is a schematic bottom view of the range hood 1 shownin FIG. 1. As shown in FIG. 1 and FIG. 2, the range hood 1 of theembodiment includes a housing 10, a cover 11, an exhaust pipe 12 and atleast two vacuum fans. In the embodiment, the number of vacuum fans isillustrated by two for the following description. However, the number ofthe vacuum fans of the invention may be more than two and the inventiondoes not limit the number of the vacuum fans. The range hood 1 of theembodiment includes a first vacuum fan 13 and a second vacuum fan 14.The housing 10 has a top opening 101 and a bottom opening 102 oppositeto each other. The cover 11 is disposed in the housing 10 and adjacentto the bottom opening 102 of the housing 10. The cover 11 has an airinlet 111 facing the bottom opening 102. The exhaust pipe 12 is disposedin the housing 10 and located between the top opening 101 of the housing10 and the cover 11. The exhaust pipe 12 has an air outlet 120 adjacentto the top opening 101 of the housing 10. The exhaust pipe 12 and thecover 11 communicate with each other. The first vacuum fan 13 and thesecond vacuum fan 14 are disposed in the cover 11 and located betweenthe air inlet 111 and the exhaust pipe 12. The first vacuum fan 13 hasan air flow inlet 131 adjacent to the air inlet 111 and an air flowoutlet 132 adjacent to the exhaust pipe 12. The second vacuum fan 14 hasan air flow inlet 141 adjacent to the air inlet 111 and an air flowoutlet 142 adjacent to the exhaust pipe 12. As shown in FIG. 1, thefirst vacuum fan 13 and the second vacuum fan 14 are disposed side byside and adjacent to each other. When the first vacuum fan 13 and thesecond vacuum fan 14 start to exhaust air, air enters the cover 11through the air inlet 111 and then enters the air flow inlet 131 of thefirst vacuum fan 13 and the air flow inlet 141 of the second vacuum fan14 and then enters the exhaust pipe 12 through the air flow outlet 132of the first vacuum fan 13 and the air flow outlet 142 of the secondvacuum fan 14. It should be noted that the number of the air flow inlets131 of the first vacuum fan 13 and the number of the air flow inlets 141of the second vacuum fan 14 are not limited in the invention. The numberof the air flow inlets 131, 141 may be more than one according to actualrequirements.

The detailed configuration of the range hood 1 of the embodiment will befurther described below.

As shown in FIG. 1 and FIG. 2, the range hood 1 of the embodimentfurther includes at least one baffle. In the embodiment, the number ofbaffles is illustrated by two for the following description. However,the number of the baffles is not limited in the invention. The rangehood 1 of the embodiment includes a first baffle 15 and a second baffle16. The first baffle 15 is disposed between the first vacuum fan 13 andthe bottom opening 102 of the housing 10. The second baffle 16 isdisposed between the second vacuum fan 14 and the bottom opening 102 ofthe housing 10. The first baffle 15 and the second baffle 16 arerespectively inclined with respect to a plane F formed by the air inlet111 of the cover 11, and the first baffle 15 and the second baffle 16are, for example, inclined toward the center of the air inlet 111 andinto the cover 11. A first angle θ1 is formed between the first baffle15 and the plane F, and a second angle θ2 is formed between the secondbaffle 16 and the plane F. It should be noted that the position of thefirst baffle 15 and the second baffle 16 is not limited in theinvention. In other embodiments, the first baffle 15 may be disposedbetween the first vacuum fan 13 and the air inlet 111 of the cover 11,and the second baffle 16 may be disposed between the second vacuum fan14 and the air inlet 111 of the cover 11.

As shown in FIG. 1 and FIG. 2, in the embodiment, the first angle θ1between the first baffle 15 and the plane F is, for example, greaterthan or equal to 0.1 degrees and less than or equal to 10 degrees, andthe second angle θ2 between the second baffle 16 and the plane F is, forexample, greater than or equal to 0.1 degrees and less than or equal to10 degrees. A first projection area R1 and a second projection area R2are formed on the plane F by the first baffle 15 and the second baffle16 respectively. The first projection area R1 of the first baffle 15 onthe plane F and the second projection area R2 of the second baffle 16 onthe plane F do not overlap each other. A gap G is formed between thefirst baffle 15 and the second baffle 16. The gap G is a distancebetween the first projection area R1 and the second projection area R2,and is greater than or equal to 2 cm and less than or equal to 10 cm. Inaddition, the cover 11 of the embodiment further has an inner wallsurface 112. An edge of the inner wall surface 112 surrounds to form theair inlet 111 of the cover 11. A first gap G1 is formed between thefirst baffle 15 and the edge of the inner wall surface 112 of the cover11. A second gap G2 is formed between the second baffle 16 and the edgeof the inner wall surface 112 of the cover 11. Specifically, in theembodiment, the first baffle 15 and the second baffle 16 arerectangular. The first gap G1 is formed between a first edge E1, asecond edge E2 and a third edge E3 of the first baffle 15 and therespective edge of the inner wall surface 112. The second gap G2 isformed between a fourth edge E4, a fifth edge E5 and a sixth edge E6 ofthe second baffle 16 and the respective edge of the inner wall surface112. When the first vacuum fan 13 and the second vacuum fan 14 start toexhaust air, air flows into the cover 11 through the gap G, the firstgaps G1 and the second gaps G2, and the first baffle 15 and the secondbaffle 16 are, for example, inclined toward the center of the air inlet111 and into the cover 11 so that most of the air flows into the cover11 along the incline direction from the gap G. In other embodiments,different gaps are formed between the first edge E1, the second edge E2and the third edge E3 of the first baffle 15 and the respective edges ofthe inner wall surface 112, and different gaps are formed between thefourth edge E4, the fifth edge E5 and the sixth edge E6 of the secondbaffle 16 and the respective edges of the inner wall surface 112, andthe invention is not limited thereto.

In the embodiment, it should be noted that the area of the air inlet 111of the cover 11 is A, the area of the air flow inlet 131 of the firstvacuum fan 13 is B1, the area of the air flow inlet 141 of the secondvacuum fan 14 is B2, the area of the first baffle 15 is C1, the area ofthe second baffle 16 is C2, and A, B1, B2, C1 and C2 satisfy theequation: A−(C1+C2)≥B1+B2. That is, the total air inlet area of the airinlet 111 of the cover 11 is greater than or equal to the sum of the airinlet area of the first vacuum fan 13 and the air inlet area of thesecond vacuum fan 14. If the first vacuum fan 13 has two air flowinlets, B1 is referred to as the air inlet area of the two air flowinlets. If the second vacuum fan 14 has two air flow inlets, B2 isreferred to as the air inlet area of the two air flow inlets.

It should be noted that the numbers of vacuum fans and baffles are notlimited in the invention. The number of the vacuum fans being two andthe number of baffles being two are only one of the embodiments of theinvention. In other embodiments, only one baffle may be disposed; thatis, the second baffle 16 is removed and only the first baffle 15 is leftin FIG. 1. In such a case, the area of the air inlet 111 of the cover 11is A, the area of the air flow inlet 131 of the first vacuum fan 13 isB1, the area of the air flow inlet 141 of the second vacuum fan 14 isB2, the area of the first baffle 15 is C1, and A, B1, B2, and C1 satisfythe equation: A−C1≥B1+B2. In yet another embodiment, no baffle may beprovided; that is, the first baffle 15 and the second baffle 16 in FIG.1 are removed. In such a case, the area of the air inlet 111 of thecover 11 is A, the area of the air flow inlet 131 of the first vacuumfan 13 is B1, the area of the air flow inlet 141 of the second vacuumfan 14 is B2, and A, B1, and B2 satisfy the equation: A≥B1+B2.

As shown in FIG. 1, the exhaust pipe 12 of the embodiment includes afirst sub pipe 121 and a second sub pipe 122. The first sub pipe 121 hasa first extending portion P1 and a first joining portion CN1 connectedwith the first extending portion P1. The second sub pipe 122 has asecond extending portion P2 and a second joining portion CN2 connectedwith the second extending portion P2. The first extending portion P1 ofthe first sub pipe 121 communicates with the air flow outlet 132 of thefirst vacuum fan 13. The second extending portion P2 of the second subpipe 122 communicates with the air flow outlet 142 of the second vacuumfan 14. The first joining portion CN1 of the first sub pipe 121 isconnected with the second joining portion CN2 of the second sub pipe122. The first joining portion CN1 has a first opening O1 adjacent tothe air outlet 120 of the exhaust pipe 12. The second joining portionCN2 has a second opening O2 adjacent to the air outlet 120 of theexhaust pipe 12. The first opening O1, the second opening O2 and the airoutlet 120 communicate with each other.

In the embodiment, the cross-sectional area CA1 of the first extendingportion P1 of the first sub pipe 121 is less than or equal to the areaB1 of the air flow inlet 131 of the first vacuum fan 13, and thecross-sectional area CA2 of the second extending portion P2 of thesecond sub pipe 122 is less than or equal to the area B2 of the air flowinlet 141 of the second vacuum fan 14. In the embodiment, the firstextending portion P1 of the first sub pipe 121 extends from the firstvacuum fan 13 toward the first joining portion CN1 so as to have a firstextending length L1. The second extending portion P2 of the second subpipe 122 extends from the second vacuum fan 14 toward the second joiningportion CN2 so as to have a second extending length L2. The firstextending length L1 and the second extending length L2 are respectivelygreater than or equal to 20 cm and less than or equal to 60 cm. In theembodiment, the area of the air outlet 120 of the exhaust pipe 12 is D,the area of the first opening O1 of the first joining portion CN1 is D1,the area of the second opening O2 of the second joining portion CN2 isD2, and D, D1 and D2 satisfy the equation: D1+D2≥D; that is, the sum ofthe area D1 of the first opening O1 and the area D2 of the secondopening O2 is greater than or equal to the area D of the air outlet 120of the exhaust pipe 12. In the embodiment, an angle θ is formed betweenan outer wall of an end of the first extending portion P1 of the firstsub pipe 121 and an outer wall of an end of the second extending portionP2 of the second sub pipe 122, and the angle θ is an acute angle.Specifically, the first extending portion P1 of the first sub pipe 121and the second extending portion P2 of the second sub pipe 122 areconnected at their ends, and the end of the first extending portions P1and the end of the second sub pipe 122 are respectively connected withthe first joining portion CN1 and the second joining portion CN2. Afterthe first vacuum fan 13 and the second vacuum fan 14 supplies airflowinto the first sub pipe 121 and the second sub pipe 122, the airflowfrom the first vacuum fan 13 is directed toward the first opening O1sequentially along the first extending portion P1 and the first joiningportion CN1, the airflow from the second vacuum fan 14 is directedtoward the second opening O2 sequentially along the second extendingportion P2 and the second joining portion CN2, and then the airflow fromthe two sub pipes is collected in the air outlet 120. By the design ofthe first extending portion P1, the second extending portion P2, thefirst joining portion CN1 and the second joining portion CN2, theexhaust path can be lengthened and the airflow in the exhaust pipe 12can be collected and exhausted from the air outlet 120 in amulti-sectional manner, which can effectively reduce the flow resistanceand noise generated by the airflow in the range hood.

As shown in FIG. 1 and FIG. 2, the range hood 1 of the embodimentfurther includes at least one blower fan. In the embodiment, the blowerfan is a cross flow fan for example, but the invention is not limitedthereto. In the embodiment, the number of blower fans is explained bytaking three as an example, but the invention does not limit the numberof the blower fans. That is, the range hood 1 of the embodiment includesa first blower fan 17, a second blower fan 18 and a third blower fan 19.In the embodiment, the housing 10 includes a first side edge 103, asecond side edge 104, a third side edge 105 and a fourth side edge 106.For the housing 10, the first side edge 103 is opposite to the secondside edge, the third side edge 105 is opposite to the fourth side edge106, the third side edge 105 is adjacent between the first side edge 103and the second side edge 104, and the fourth side edge 106 is adjacentbetween the first side edge 103 and the second side edge 104. The firstside edge 103, the second side edge 104, the third side edge 105 and thefourth side edge 106 surround to form the bottom opening 102 of thehousing 10. The first blower fan 17, the second blower fan 18 and thethird blower fan 19 are respectively located between the housing 10 andthe cover 11. The first blower fan 17 is disposed on the first side edge103 of the housing 10, the second blower fan 18 is disposed on thesecond side edge 104 of the housing 10, and the third blower fan 19 isdisposed on the third side edge 105 of the housing 10. The first blowerfan 17 has a gas outlet 171 adjacent to the bottom opening 102 of thehousing 10 and a gas inlet 172 away from the bottom opening 102 of thehousing 10. Likewise, the second blower fan 18 has a gas outlet 181adjacent to the bottom opening 102 of the housing 10 and a gas inlet 182away from the bottom opening 102 of the housing 10, and the third blowerfan 19 has a gas outlet 191 adjacent to the bottom opening 102 of thehousing 10 and a gas inlet (not shown) away from the bottom opening 102of the housing 10. In the embodiment, the gas inlet 172 of the firstblower fan 17, the gas inlet 182 of the second blower fan 18 and the gasinlet of the third blower fan 19 are respectively opposite to theopenings of the gas outlets 171, 181 and 191. However, in otherembodiments, the openings of the gas inlets may be perpendicular to theopenings of the gas outlet, and the invention is not limited thereto.

In the embodiment, the gas outlet 171 of the first blower fan 17 extendsalong the first side edge 103 of the housing 10 so as to have anextending length L1′, and the extending length L1′ is greater than orequal to 70% and less than 100% of the length of the first side edge103. The gas outlet 181 of the second blower fan 18 extends along thesecond side edge 104 of the housing 10 so as to have an extending lengthL2′, and the extending length L2′ is greater than or equal to 70% andless than 100% of the length of the second side edge 104. The gas outlet191 of the third blower fan 19 extends along the third side edge 105 ofthe housing 10 so as to have an extending length L3′, and the extendinglength L3′ is greater than or equal to 70% and less than 100% of thelength of the third side edge 105. In the embodiment, the air volumeoutputted from the gas outlets 171, 181 and 191 of the first blower fan17, the second blower fan 18 and the third blower fan 19 within a fixedtime period is less than the air volume inputted from the air flowinlets 131 and 141 of the first vacuum fan 13 and the second vacuum fan14 within the above fixed time period respectively. The first blower fan17, the second blower fan 18, and the third blower fan 19 input air fromthe outside of the range hood 1 and blow the air toward the bottom ofthe range hood 1 via the gas outlets 171, 181 and 191 so as to form areturn air wall around the periphery of a cooking area under the rangehood 1, so as to enclose the fumes generated in the cooking area andblock the fumes from leaking out of the cooking area. Further, by thevacuum fans 13 and 14, the return air wall and the fume enclosed by thereturn air wall are directed to the gap G, the first gaps G1 and thesecond gaps G2 and into the housing 11, and finally are exhaustedthrough the exhaust pipe 12.

It is to be noted that the number of the blower fans is not limited inthe invention. The range hood 1 having three blower fans is only one ofthe embodiments of the invention. In other embodiments, the range hood 1may have only one blower fan, and this blower fan may be disposed on anyone of the first side edge 103, the second side edge 104, the third sideedge 105 and the fourth side edge 106 of the housing 10. In stillanother embodiment, the range hood 1 may have only two blower fans, andthe two blower fans may be disposed on any two of the first side edge103, the second side edge 104, the third side edge 105 and the fourthside edge 106 of the housing 10.

Please refer to FIG. 3 and FIG. 4. FIG. 3 is a schematic diagram of theresistance difference between the range hood 1 of the invention and theconventional range hood. FIG. 4 is a schematic diagram of the noise flowcurve difference between the range hood 1 of the invention and theconventional range hood. As shown in FIG. 3, at a flow rate of 500 cfm(cubic feet per minute), the conventional range hood has a systemresistance of 30 mmH₂O (millimeters of water) and the range hood 1 ofthe invention has a system resistance of 24 mmH₂O; that is, the systemresistance of the range hood 1 of the invention is improved about 20%,compared with that of the conventional range hood. As shown in FIG. 4,at the same airflow rate of 550 cfm for example, the range hood 1 of theinvention reduces the noise of about 10 dB, compared with theconventional range hood. It can be seen that in the design of the rangehood 1 of the invention, the lower system resistance not only allows thevacuum fan to be able to generate the same airflow volume at a lowerspeed, but also appreciably reduces the noise by having thecharacteristics of lower fan speed and smoother airflow field, thusachieving the purpose of having both low noise and high fume-exhaustingperformance at the same time.

Please refer to FIG. 5, which is a schematic bottom view of a range hood1 a in accordance with another embodiment of the invention. The rangehood 1 a of the embodiment is similar to the range hood 1 shown in FIG.1 and FIG. 2, and the difference lies in that the range hood 1 a of theembodiment further includes a third baffle 20. As shown in FIG. 5, inthe embodiment, the third baffle 20 is disposed adjacent to the firstbaffle 15 and the second baffle 16. The first baffle 15, the secondbaffle 16 and the third baffle 20 are, for example, inclined toward thecenter of the air inlet 111 and into the cover 11. However, theinvention does not limit the arrangement of the first baffle 15, thesecond baffle 16 and the third baffle 20. The arrangement of the firstbaffle 15, the second baffle 16 and the third baffle 20 may varyaccording to the actual requirements. The first projection area R1 ofthe first baffle 15 on the plane F, the second projection area R2 of thesecond baffle 16 on the plane F and the third projection area R3 of thethird baffle 20 on the plane F do not overlap each other.

Please refer to FIG. 6, which is a schematic bottom view of a range hood1 b in accordance with another embodiment of the invention. The rangehood 1 b of the embodiment is similar to the range hood 1 a shown inFIG. 3, and the difference lies in that the range hood 1 b of theembodiment further includes a fourth baffle 21. As shown in FIG. 6, inthe embodiment, the first baffle 15, the second baffle 16, the thirdbaffle 20 and the fourth baffle 21 are arranged as an array. The firstbaffle 15, the second baffle 16, the third baffle 20 and the fourthbaffle 21 are, for example, inclined toward the center of the air inlet111 and into the cover 11. However, the invention does not limit thearrangement of the first baffle 15, the second baffle 16, the thirdbaffle 20 and the fourth baffle 21. The arrangement of the first baffle15, the second baffle 16, the third baffle 20 and the fourth baffle 21may vary according to the actual requirements. The first projection areaR1 of the first baffle 15 on the plane F, the second projection area R2of the second baffle 16 on the plane F, the third projection area R3 ofthe third baffle 20 on the plane F and the fourth projection area R4 ofthe fourth baffle 21 on the plane F do not overlap each other.

Please refer to FIG. 7, which is a schematic view of the structure of arange hood 1 c in accordance with another embodiment of the invention.The range hood 1 c of the embodiment is similar to the range hood 1shown in FIG. 1 and FIG. 2, and the difference lies in that the rangehood 1 c of the embodiment further includes a first guard board 22 and asecond guard board 23. The first guard board 22 is disposed between thefirst side edge 103 of the housing 10 and the cover 11, and the firstguard board 22 is adjacent to the first blower fan 17. The second guardboard 23 is disposed between the second side edge 104 of the housing 10and the cover 11, and the second guard board 23 is adjacent to thesecond blower fan 18. In the embodiment, the first guard board 22 andthe second guard board 23 respectively extend toward a lower side of thehousing 10 so as to prevent the fume from leaking out of the cookingarea under the range hood 1 c. It is to be noted that the first guardboard 22 and the second guard board 23 of the embodiment may beaccommodated in the housing 10.

In summary, according to the embodiments of the invention, the structureof the range hood optimizes the airflow field of the inflow and outflowof air. The airflow field during the whole fume-exhausting process istapered in a multi-section manner so as to achieve smooth exhaustion offumes, improve the flow resistance of the range hood, and further reducenoise. In addition, by the components such as the blower fan and thebaffle, the range hood of the embodiments of the invention prevents thefumes from diffusing to the outside of the range hood so as to improvethe efficiency of fume exhausting.

The foregoing description of the preferred embodiment of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform or to exemplary embodiments disclosed. Accordingly, the foregoingdescription should be regarded as illustrative rather than restrictive.Obviously, many modifications and variations will be apparent topractitioners skilled in this art. The embodiments are chosen anddescribed in order to best explain the principles of the invention andits best mode practical application, thereby to enable persons skilledin the art to understand the invention for various embodiments and withvarious modifications as are suited to the particular use orimplementation contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and their equivalentsin which all terms are meant in their broadest reasonable sense unlessotherwise indicated. Therefore, the term “the invention”, “Theinvention” or the like is not necessary limited the claim scope to aspecific embodiment, and the reference to particularly preferredexemplary embodiments of the invention does not imply a limitation onthe invention, and no such limitation is to be inferred. The inventionis limited only by the spirit and scope of the appended claims.Moreover, these claims may refer to use “first”, “second”, etc.following with noun or element. Such terms should be understood as anomenclature and should not be construed as giving the limitation on thenumber of the elements modified by such nomenclature unless specificnumber has been given. The abstract of the disclosure is provided tocomply with the rules requiring an abstract, which will allow a searcherto quickly ascertain the subject matter of the technical disclosure ofany patent issued from this disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Any advantages and benefits described may notapply to all embodiments of the invention. It should be appreciated thatvariations may be made in the embodiments described by persons skilledin the art without departing from the scope of the invention as definedby the following claims. Moreover, no element and component in thedisclosure is intended to be dedicated to the public regardless ofwhether the element or component is explicitly recited in the followingclaims. Furthermore, the terms such as the first vacuum fan, the secondvacuum fan, the first baffle, the second baffle and so on are only usedfor distinguishing various elements and do not limit the number of theelements.

What is claimed is:
 1. A range hood, comprising: a housing, having a topopening and a bottom opening opposite to each other; a cover, disposedin the housing and adjacent to the bottom opening of the housing,wherein the cover has an air inlet facing the bottom opening; an exhaustpipe, disposed in the housing and located between the top opening of thehousing and the cover, wherein the exhaust pipe has an air outletadjacent to the top opening, and the exhaust pipe and the covercommunicate with each other; and at least two vacuum fans, disposed inthe cover and located between the air inlet and the exhaust pipe,wherein each of the at least two vacuum fans has an air flow inletadjacent to the air inlet and an air flow outlet adjacent to the exhaustpipe, and an area of the air inlet of the cover is greater than or equalto an area of the air flow inlets of the at least two vacuum fans. 2.The range hood according to claim 1, further comprising at least onebaffle disposed between the at least two vacuum fans and the bottomopening of the housing, wherein the least one baffle is inclined withrespect to a plane formed by the air inlet of the cover so as to form anangle with respect to the plane.
 3. The range hood according to claim 2,wherein the angle between the at least one baffle and the plane isgreater than or equal to 0.1 degrees and less than or equal to 10degrees.
 4. The range hood according to claim 2, wherein the coverfurther has an inner wall surface, an edge of the inner wall surfacesurrounds to form the air inlet of the cover, and a gap is formedbetween the at least one baffle and the edge of the inner wall surfaceof the cover.
 5. The range hood according to claim 2, wherein an area ofthe air inlet of the cover is A, an area of the air flow inlets of theat least two vacuum fans is B, an area of the baffle is C, and A−C≥B. 6.The range hood according to claim 2, wherein a number of the at leastone baffle is plural, the at least one baffle comprises a first baffleand a second baffle, the at least two vacuum fans comprise a firstvacuum fan and a second vacuum fan, the first baffle is located betweenthe first vacuum fan and the bottom opening of the housing, and thesecond baffle is located between the second vacuum fan and the bottomopening of the housing.
 7. The range hood according to claim 6, whereina first projection area of the first baffle on the plane and a secondprojection area of the second baffle on the plane do not overlap eachother.
 8. The range hood according to claim 6, wherein a gap is formedbetween the first baffle and the second baffle, and the gap is greaterthan or equal to 2 cm and less than or equal to 10 cm.
 9. The range hoodaccording to claim 6, wherein an area of the air inlet of the cover isA′, an area of the air flow inlet of the first vacuum fan is B1, an areaof the air flow inlet of the second vacuum fan is B2, an area of thefirst baffle is C1, an area of the second baffle is C2, andA′−(C1+C2)≥B1+B2.
 10. The range hood according to claim 2, wherein anumber of the at least one baffle is plural, the at least one bafflecomprises a first baffle, a second baffle and a third baffle, whereinthe first baffle, the second baffle and the third baffle are disposedadjacent to one another, wherein a first projection area of the firstbaffle on the plane, a second projection area of the second baffle onthe plane and a third projection area of the third baffle on the planedo not overlap each other.
 11. The range hood according to claim 2,wherein a number of the at least one baffle is plural, the at least onebaffle comprises a first baffle, a second baffle, a third baffle and afourth baffle, wherein the first baffle, the second baffle, the thirdbaffle and the fourth baffle are arranged as an array, wherein a firstprojection area of the first baffle on the plane, a second projectionarea of the second baffle on the plane, a third projection area of thethird baffle on the plane and a fourth projection area of the fourthbaffle on the plane do not overlap each other.
 12. The range hoodaccording to claim 1, wherein the at least two vacuum fans comprise afirst vacuum fan and a second vacuum fan, the exhaust pipe comprises afirst sub pipe and a second sub pipe, the first sub pipe has a firstextending portion, the second sub pipe has a second extending portion,the first extending portion communicates with the air flow outlet of thefirst vacuum fan, the second extending portion communicates with the airflow outlet of the second vacuum fan, a cross-sectional area of thefirst extending portion is less than or equal to an area of the air flowinlet of the first vacuum fan, and a cross-sectional area of the secondextending portion is less than or equal to an area of the air flow inletof the second vacuum fan.
 13. The range hood according to claim 12,wherein the first sub pipe has a first joining portion connected withthe first extending portion, the second sub pipe has a second joiningportion connected with the second extending portion, the first joiningportion is connected with the second joining portion, the first joiningportion has a first opening adjacent to the air outlet, the secondjoining portion has a second opening adjacent to the air outlet, and thefirst opening, the second opening and the air outlet communicate witheach other.
 14. The range hood according to claim 13, wherein the firstextending portion extends from the first vacuum fan toward the firstjoining portion so as to have a first extending length, the secondextending portion extends from the second vacuum fan toward the secondjoining portion so as to have a second extending length, and the firstextending length and the second extending length respectively aregreater than or equal to 20 cm and less than or equal to 60 cm.
 15. Therange hood according to claim 13, wherein an area of the air outlet isD, an area of the first opening of the first joining portion is D1, anarea of the second opening of the second joining portion is D2, andD1+D2≥D.
 16. The range hood according to claim 13, wherein an angle isformed between an end of the first extending portion and an end of thesecond extending portion, and the angle is an acute angle.
 17. The rangehood according to claim 1, further comprising at least one blower fandisposed between the housing and the cover, wherein the blower fan has agas outlet adjacent to the bottom opening of the housing and a gas inletaway from the bottom opening of the housing.
 18. The range hoodaccording to claim 17, wherein an air volume outputted from the gasoutlet of the blower fan within a time period is less than an air volumeinputted from the air flow inlet of the vacuum fan within the timeperiod.
 19. The range hood according to claim 17, wherein the housingfurther has a plurality of side edges, the side edges surround to formthe bottom opening, the blower fan is disposed on one of the side edges,the gas outlet of the blower fan extends along one of the side edges soas to have an extending length, and the extending length is greater thanor equal to 70% and less than 100% of a length of one of the side edges.20. The range hood according to claim 19, wherein the side edgescomprise a first side edge, a second side edge, a third side edge and afourth side edge, the first side edge is opposite to the second sideedge, the third side edge is opposite to the fourth side edge, the thirdside is adjacent to the first side edge and the second side edge, thefourth side edge is adjacent to the first side edge and the second sideedge, a number of the at least one blower fan is plural, the at leastone blower fan comprises a first blower fan, a second blower fan and athird blower fan, the first blower fan is disposed on the first sideedge, the second blower fan is disposed on the second side edge, and thethird blower fan is disposed on the third side edge.